Generic operator workplaces of construction machines, especially for a milling machine for processing of a road surface, usually comprise a seat with a respective seating surface with a planar and substantially horizontal seating surface. Frequently, there is a backrest in order to provide the operator with a comfortable sitting position. An armrest is arranged to the side of the seating surface which comprises a supporting surface for the arm. The relative position of the armrest or the supporting surface for the arm in relation to the seating surface and back surface is chosen in such a way that the operator who sits in the seat can allow the arm to rest on the supporting surface of the armrest in a bent manner. It is obviously also possible to provide one such armrest on each of the two sides of the seating surface. It is further common practice to arrange control elements such as multifunctional control elements, e.g. in the form of a joystick control, for controlling at least one machine function in the armrest. This special embodiment of an operator workplace allows the operator to control the construction machine even over prolonged periods of time in a comfortable and ergonomically positive body posture because he is able to place the arm on the supporting surface of the armrest and at the same time is able to perform control functions on the construction machine with the control element integrated in the armrest. A generic operator workplace is known for example from DE 10 2006 015 504 A1.
Situations frequently occur in the daily operation of a construction machine where limited visibility from the sitting position of the machine operator prevents precise guidance of the machine. This occurs especially frequently in milling machines for processing a road surface where a milling roll needs to be guided as precisely as possible over the road surface to be removed. Many machine operators will change especially in such situations from a seated position to a standing position in order to gain a better view of the working area and/or boundary area to be processed and to thus achieve a more precise guidance of the construction machine over the ground. It is therefore known from DE 10 2006 015 504 A1 to provide the backrest of the seat of the operator workplace to be pivotable towards the driver, so that he can use the upper end of the backrest as a seat in a semi-sitting/standing position. In order to enable the machine operator to securely guide the construction machine both in his sitting position as well as in his leaning seating/standing position, the steering wheel positioned in the working direction of the construction machine in front of the machine operator can be swiveled upwardly about a horizontal pivoting axis between an inclined position to a flatter position and vice versa. Following each change between the sitting position and the standing or sitting/standing position, the operator needs to adjust his arm posture. At the same time, the control of the at least one control element in the armrest is very tiring and ergonomically unfavorable especially in the standing position because there is no supporting feature for the operator's arm that performs the control. In modern road milling machines however an increasing number of functions are integrated as control elements in the armrest arranged to the side of the machine operator and partly there is even no steering wheel, and steering control is also performed via control elements on the armrest. This will often lead to fatigue phenomena in various positions of the operator.
The armrest is usually rigidly arranged on the seat and merely allows a minimal height adjustment for various operators in the respective sitting position, if at all. Conventional adjusting paths lie in the range for example up to a maximum of 10 cm in the vertical direction. If the machine operator changes from his sitting position to the standing position, the position of his arm will change relative to the control element integrated in the armrest. This will frequently be perceived as disadvantageous because the control element functions cannot be operated similarly from the sitting position and the standing position. Moreover, the operation of the control elements integrated in the armrest is especially strenuous for the machine operator in the standing position because the arm is then not able to rest on the armrest and he needs to operate the control elements in an exceptionally uncomfortable inclined position of the arm, especially forearm.
It is therefore the object of the invention to provide an operator workplace which is improved with respect to operating comfort and functionality in comparison with previous operator workplaces of construction machines, especially milling machines for processing a road surface.